Fatigue damage study in aluminum-2024 T3 alloys

The grain structure of aluminum 2024, a commonly used commercial alloy is investigated, and these findings are correlated with the fatigue property of the material. Samples of aluminum 2024 were polished and etched in different reagents. Optical micrographs (at 500X) of samples etched in Keller's reagent revealed grain boundaries as well as some particles present in the microstructure. Normal x-ray scans of samples etched for different intervals of time in Keller's reagent indicate no significant variations in diffraction peak positions; however, the width of the rocking curve increased with the time of etching. These results are consistent with the direct dependence of the width of the rocking curve on the range of grain orientation. Etching removes the preferred orientation layer of the sample produced by polishing; thereby, causing the width to increase.